<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>
<body>
    <p id="p"></p>
    <script>
        setInterval(function(){
        var oDate=new Date();
        var hour=oDate.getHours();
        var minute=oDate.getMinutes();
        var seconds=oDate.getSeconds();
        function transform(params){
            // if (params<10){
            //     params="0"+params
            // }
            return params=params<10?"0"+params:params;
        }
        hour=transform(hour)
        minute=transform(minute)
        seconds=transform(seconds)
        var sum=hour+":"+minute+":"+seconds
        var p=document.getElementById("p")
        p.innerHTML=sum
        // console.log(sum)
    },1000)
    </script>
</body>
</html>